To the editor

This letter concerns my recent review of the book, Decoding Darkness: The Search for the Genetic Causes of Alzheimer's Disease by Rudolph Tanzi and Ann Parson1. Several errors have been pointed out to me and I would like to alert readers to these. First, the 'errors in fact' mentioned in the review were few and of a minor nature. Second, an allusion was made regarding the confusion of the original linkage of the Massachusetts General Hospital families with familial Alzheimer's disease (AD) to chromosome 21, which was subsequently shown to contain a presenilin 1 mutation. I thought the text might have explained the reassignment of the gene locus from chromosome 21 to 14 in a way that could confuse the casual reader. In fact, the book clearly explains that lod (logarithm of the odds) scores are statistical results that are prone to error, as in the initial assignment of chromosome 21. The statement that the readers might be left hanging on some of these issues was therefore inappropriate.

The achievements in AD research by Rudy Tanzi's laboratory within the past two decades have been outstanding. The presentation of these achievements, and those of others, in a book such as Decoding Darkness provides an invaluable reference for AD researchers and much information and inspiration for the general public. I hope that readers will share my overall excitement about the book and its many positive aspects and not be distracted by the minor concerns that were expressed in the review.